Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Human triggered avalanches will be likely at the middle and upper elevations by early afternoon today. While most of these avalanches will just involve the recent storm snow there remains the possibility to trigger a very large avalanche in isolated areas. If triggered, very large avalanches have the potential to run full track down to drainage bottoms and affect common travel corridors. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2

    Up to 12 inches of new storm snow is possible by early this evening, with westerly winds in the 25-35 mph range (gusts in excess of 40 mph). This will build wind slabs that could be 1-2 feet thick and sensitive to human triggering. This snow lies on a variety of old snow surfaces, including - but not limited to - sun crusts, windboard, laid down surface hoar, and possibly small near surface facets. A poorly defined frontal passage is on deck for this afternoon/evening.  

    Moniter the wind direction and look for evidence of cracking within wind drifted snow. 

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3

    A weak basal structure is present on previously wind scoured aspects. This layer is 20 to 60 cm above the ground and 50 to 100 cm down from the surface in areas that correspond to the highest likelihood of human triggering. While finding the sour spot is unlikely the resulting avalanche will be very large.

    Todays storm will increase the number of possible triggers through sloughing, cornice failure, rapid loading, and other smaller avalanches. 

    The only way to rule out this problem is by digging a hole in or near the slope you plan to ski or ride. 

Avalanche Discussion

Today will bring an interesting confluence of avalanche problems. The Greys are currently in the midst of a 48 hour long loading period that is being provided by a moist NW flow. Weather highlights include snowfall rates in the 1 inch per hour range and possible storm water totals in excess of 1.5 inches by  Saturday evening. Winds will be westerly and moderate to strong at ridgeline. 

This is a welcome reprieve from a relatively dry NNW flow regime that has left the various southern ranges with a variety of snow surfaces and riding conditions. Recent avalanches have been confined to dry loose activity.  

Current snow depths range from less than a meter on previously wind scoured aspects to well over 2 meters deep on leeward aspects at the upper elevations. Westerly winds will work to cross load southerly slopes today and build overall slab thicknesses. Significant settlement (and subsequent slab cohesion and tensile strength) should occur over the next 48 hours or so.  

Regions covered